Register for free to
view the full innovation profile.
This type of sensor functionality cannot be achieved under today’s ‘system on a chip’ paradigm, which still requires external power supplies for electronic memory function.
About
Background: A sensor concept based on reflected electromaterial signatures (REMS) consists of three distinct components working together to provide passive sensing capability of environment information: (1) the electromaterial line, a chemical strip sandwiched between the ground plane and top trace of an RF tag’s microstrip transmission line; (2) the reflector circuitry, consists of the transmission line itself, the radio-frequency integrated circuit (RFIC) that performs backscatter and identification functions, and any RF tag antennas; and (3) an RF reader must be used to interrogate the REMS sensor as well as perform the signal processing for data extraction. Conceivably, the REMS concept could be implemented with existing UHF or microwave passive RFID integrated circuits, greatly lowering cost and allowing passive interrogation of the sensor. In a conventional backscatter RFID system, the signal is reflected from a binary-switched load, providing two potential frequency-dependent measurements for extracting material line parameters. Since an RFID reader filters out unmodulated scatter components, an RFID-based REMS sensor would allow a much more precise measurement compared to other forms of remote sensing. Any material that has environmental sensitivity to permeability, permittivity, or conductivity may be a candidate for the electro-material line in the REMS sensor. For example, a simple instantaneous temperature sensor could incorporate thermotropic liquid crystals. These types of liquid crystals experience state disordering upon heating, leading to a change in their electrical (and optical) properties. A common, everyday example of these liquid crystals is the disposable thermometer magnets that allow temperature readouts to become visible through a graded liquid crystal film. Another example of candidate material may be a line substrate doped with ferroelectric or super-paramagnetic particles. Such a device could use the nonlinear relationship between field and flux density components to sense external field strengths. The REMS sensor concept may also allow for materials that time-record environmental attributes, thus providing a form of chemical memory rather than electrical memory that would achieve a completely passive sensor. This type of sensor functionality cannot be achieved under today’s ‘system on a chip’ paradigm, which still requires external power supplies for electronic memory recording functions.